THough none of us have driven this thing yet, you know were all already thinging about it - Boost! From the few pics I've seen of this engine, it does not look very friendly to a turbo or supercharger setup. But beyond that does any one know how well it would take to a lil force feeding?

For instance, do we know what kind of air meetering system it will use? Is the fuel fed with a traditional return line system or is it the more recnet style of returnless? Do we know how big the fuel injectors are? Or what style?

Do we know anything about the strenght of this transmition or rearend?

I have not seen the engine bay, but from what I have heard there is no room for a turbo or supercharger. :(
That would really suck if its true.

Jason

Originally posted by Jason
I have not seen the engine bay, but from what I have heard there is no room for a turbo or supercharger. :(
That would really suck if its true.

Jason But it would also mean that the MPS RX-8 would be NA :D

I hate turbos, and if I can avoid them I'd like to. NA rules supreme!

all motor! :D :D

though boost IS a very tempting proposition, like the dark side of the Force ;)

I'm sure someone will boost it. RE amemiya perhaps... pan speed. Greddy; hks; blitz.. SOMEONE PLEASE!!!!

LIke Igoslow said, someone will FI the engine. The rotary has way to much FI in its history for some aftermarket not to. My thought on this is that the entire runner system will have to be eliminated for FI. Not to mention the dual throttle bodies. With the torque FI would add the variable exhaust length will not be needed. The question would be at what RPM the engine would start producing power over stock. This I'm sure will make the engine peaky to say the least.

I think the better bet is to get an aftermarket intake, headers, and exhaust, this coupled with some aftermarket cpu or ecu management system I am sure we'll see 300 hp. Though a low boost supercharger or belt driven centrifugal charger might be a viable option for performance.

I went to NAIAS, and the Mazda rep took the plastic covers off the engine for me so I could take a look. There seemed to be enought room to me.

The current prevailing rumor is that the base model 4th gen RX-7 will get a 1.5L NA engine. So then what will they put in the MPS version, maybe a turbo 1.5L? It's incomprehensible that the turbo rotary is gone forever, I'm sure we'll get another one someday, somehow...

Trust me...throw a low-inertia true ball bearing turbo, something larger than the Garrett GT25 used on the Protoge, say a 30 series and it'll build the bottom end and midrange quite nicely. Those turbos, sized properly with a divided manifold and turbine housing would EASILY make 12psi @2500 rpm on a rotary. I guess the issue is for me whether or not the actual rotors themselves are any weaker than the 13B-REW rotors. I know that SR Motorsports has the intention of purchasing a renesis as soon as one becomes available. www.srx7.com.

this issue with not having enough room in the engine bay... i thought the Renesis was more compact than 13B REW, and mounted further back and lower. and doesn't seem like the 8 has smaller front end than the 7, so shouldn't room not be an issue? personally, i'd like to see them do a similar sequential twin turbo system as in the 13B REW, but that's unlikely, i guess. or is it? bearing in mind that maz was the first company to apply such a turbo system in a road car, it'd be such a shame to see it gone

Maybe I'm off base here, but I think most FD owners would beg to differ. Most of the ones I've talked to and read about on the forums and lists prefer a single, ball-bearing unit.

A single turbo sound better. I wouldnt be concerned with engine room.

My cougar has the most cluttered engine bay ive ever seen (changin plugs is a knuckle buster) and they still managed to design a kit for it. The RX8 appears to have much more room.

One of the problems with the sequential turbo systems is that the manifold is very complicated and more importantly, restrictive. Restriction on a rotary is not a good thing due to hot gas reversion back into the combustion cycle. Since rotaries have a higher EGT than piston engines, it's very important to allow an easy path for the exhaust to exit. It's bad enough with a single turbo but very bad with the sequentials.

I do occasionally miss the instant boost of the twins. But I bought a single turbo that's waaaay to big for the street, especially with stock ports.

Like I said before though, the newest turbo designs with full ball bearing cartridges are just as responsive, flow more CFM, heat the air less, and give KILLER top end power. There's almost no reason to go twin anymore unless you have a vee configuration boinger (pistons).

As far as room, the 13B-REW and the Renesis are identical in size (at least the actual short block is). Clearance isues might arise if there's not enough room for a good turbo manifold design between the side of the engine and the shock tower aseembly. And possibly the firewall. It almost looks like we're going to have to put the car on the lift to change the spark plugs! It's bad enough on the third gen...

Michel
95RX7

There's no real need for sequential twin turbos anymore, you can get about the same responsiveness from a single, and believe me, you don't want the extra complexity or heat.

If I wanted to spend the money, I would definitely ditch the twins on my FD and replace them with a moderate-sized single turbo. Lots of power and response everywhere, I'm not looking to make big hp numbers, 330 rwhp is good enough for me. :p

The last of the Japanese sequential twin turbo cars (FD, Supra, GT-R) rolled off the assembly line last summer. Japan will never again produce another sequential twin turbo car, I'd bet my life on it.

at least they were cool at the time

Originally posted by Jason
I have not seen the engine bay, but from what I have heard there is no room for a turbo or supercharger. :(
That would really suck if its true.

Jason If someone wants to buy a rx8 and bring it to my house, I can prove otherwise :DOriginally posted by fritts
The question would be at what RPM the engine would start producing power over stock. This I'm sure will make the engine peaky to say the least.Fitted with the proper turbo for the application, you could make more torque at low rpms. Thats what they did with the second gen rx7 turbo ii. The NA version is rather peaky where as its FI counterpart is making peak tq at 3300rpm and peak hp high 5000s/low 6000s.
Originally posted by chinx
personally, i'd like to see them do a similar sequential twin turbo system as in the 13B REW, but that's unlikely, i guess. or is it? bearing in mind that maz was the first company to apply such a turbo system in a road car, it'd be such a shame to see it gone The sequential turbos is what ruined the fd. A simple single turbo like the 2nd gen wouldve been better.

This might sound weird but after reading the press kit I think the perfect engine to FI is the automatic lowpower version.

Its a 4 port!! NO DUAL INTAKES! no aux ports to deal with simple. just hook up a turbo, blower, N2O kit to the existing intake tract and you got your self a power engine.

The 4 port design is why the lowpower version has more torque.

If you put FI on this engine you wouldn't have to worry about removing any of the intake track.

Originally posted by rototlewski
This might sound weird but after reading the press kit I think the perfect engine to FI is the automatic lowpower version.

Its a 4 port!! NO DUAL INTAKES! no aux ports to deal with simple. just hook up a turbo, blower, N2O kit to the existing intake tract and you got your self a power engine.

The 4 port design is why the lowpower version has more torque.

If you put FI on this engine you wouldn't have to worry about removing any of the intake track. It's not all that wierd. The automatic engines in Miatas, for example, have lower compression, which makes them better candidates for FI.

But you have to remember that the automatic engine in THIS car is also rev-limited, which kills any advantage from the 4-port setup. Still, we might see tuners take a 4-port block and make 9k revving turbo engines out of them. We'll have to wait until these guys get there hands on the car.

---jps

well, i thought the rev limit was because of the limits of the Torque Convertor... so unless your talking about a tranny swap as well, It sounds like the rev limit will have to stay for now...

It'll really depend on what tasks Mazda has assigned to the engine's ECU. A seperate ECU could be controlling the transmission and it may contain a rev limit function. The 6 port will be a bit more complicated to pressurize but it'll make substantially more hp at lower boost levels thanks to less restriction on the intake side, especially with a turbo. A roots type SC wouldn't see as much of a benefit down low due to increased volume and flow characteristics of the 6 port design. I'm sure that some aftermarket company will come out with a stand alone, whether it's Apexi with a PFC or AEM. Something will be released. But I suspect that the auto versions will have auxiliary ECU's which won't allow for total control from just one box, ie. it'll have to control or work around a seperate transmission ECU. The compression ratio for both versions is identical, is it not? I see that as being the largest hurdle to forced induction.

I think Mazda might actually be planning to throw some boost at the Renesis. I pulled a couple of quotes from Rotarynews.com

"All we can say here is: MazdaSpeed-8! We hear that a blown version of the car is in the works as we write. No confirmation of this going into production, but the car should just plain rock! The concept has already been shown at the Tokyo Auto-Saloon, and with a little boost from a turbo or super charger, watch out! "

And from the test drive impressions II

"I excused myself to the group for the technical questions, I was about to ask, that I knew they wouldn’t understand, and I started in. Obviously, one of my first inquiries was about porting the RENESIS. The motor will be able to be ported, but great care will have to be taken when grinding on the housing. Mazda has gone to great lengths to work with airflow and fuel atomization. There is a third injector per rotor sticking right in the intake port, as it enters the housing, which will have to be dealt with when cleaning up and porting the housings (see press kit information). Both the intake and exhaust ports can be cleaned up some and used for further power development in the new motor. The interesting thing is; the engineers said that doing a little port work down on both ports, might actually make a bigger difference in power than porting up, in a traditional manner. The RENESIS’ rotors are definitely lighter than previous Mazda rotaries. When picking them up, one can actually feel a big difference. Another question, that actually took me a drawing before the engineer understood, was did the 6-port sleeves have a radius in them to help smooth the air/fuel charge transition into the combustion chamber? The answer was a very pleasant; yes they do. The Engineer was actually quite surprised at our technical line of questioning, but he had been warned about the two Rotorheads who might be crashing the party. The time in the engine session flew by quick and soon they were booting us out of the room. We hadn’t noticed everyone else had been gone for a while, and they were waiting for us. Side note here: Almost all of my engine questions were under the assumption of Motorsport usage and didn’t take into account emissions and such. Overall though, the RENESIS is still a Rotary and I’m sure we are going to start seeing the Race and Aftermarket communities have it soon. Can you imagine, a 12000RPM RENESIS street motor, nice! Oh yea, before I forget, the engineer did mention one more important thing; the motor was built to take boost!"

yeah I remember that. Goddamn it! I want mazda to sell them as crate engines. Maybe just the shortblock but even then it would be easier to fab the manifolds and work with the motor.
With this being brand new it would suck to make some fatal porting mistake on your brand new RX-8 and who knows how much the dealers will charge to fix it or replace the engine is more likely. But hell who would want to get one just to play around with?

So their opinion was that the rotors, as they are, will handle boost? how are we going to lower the compression ratio without modifying the bathtub? I was under the assumption that was a no no? I too feel as though we'll see a boosted renesis.
Michel

apparently so. either that, or they have a lower compression rotor made for turbocharging.

I was actually (sarcasm) thinking a couple nights back about aftermarket turbo kits. With the complexity and the high compression ratio of the stock Renesis, I do believe I'll be waiting for a Mazdaspeed-boosted Renesis. The as is design is very much optimized to run naturally aspirated. As such, designing an aftermarket kit would be highly complex, limited, and probably wouldn't satisfy the hp junkie in me. I'd at least stay away from it in the first couple of years. The need for lower compression rotors alone would keep me away. The aftermarket is pretty ingenious however, so we'll have to see what they come up with.
Michel

has anybody heard when the mazdaspeed 8 is supposed to be released?

Ok, being an engineer by training (all be it, Software engineer, but I had to take EE and ME courses too) , I've been doing some sketches of how and where a supercharger kit would be.

My conclusion is almost the entire intake system will have to be redone, from the block to the throttle bodies. Nothing like the cadmin kit could be done, because of space requirements.

I think the 3 intake tracts would need to be removed, the super charger placed between the injectors and the air sensor.

Attached a rough image of what I think a Cadmen -style supercharger setup would look like on the FE.

Red blocks are injectors, and this sketch isn't in 3dimensions, so the supercharger could sit closer and further down than this sketch indicates. A single large intake tube would be connected to the top of the super charger , and all vacuum could be drawn from there, At the end of that tube would be the modified Air flow meter. I would suspect a computer mod would needed to be done, maybe even swapping it out for a Haltech or otehr aftermarket ECU.


Now, again, this is just my back-of-the-napkin engineering going on... those 2/3 intake tracks have me worried about aftermarket supercharger kits, however.

Originally posted by rotarynews.com
I think the 3 intake tracts would need to be removed, the super charger placed between the injectors and the air sensor... I would think so too, and normally, a roots type (if that is what you are envisioning) is also usually downstream of the throttlebody too.

---jps

Is anyone else worried that a supercharger might throw off the car's inherent weight balance a little?

One of the beauties of the Renesis is that its diminutive size allowed the engineers to place it way back and way down inside the car, giving the car a more centralized weight distribution and thus a lower moment of yaw inertia. Bolting a supercharger on top of the engine would raise its (the engine's) center of gravity. Would this change be noticeable at all?

Also, would it actually be better to bolt a supercharger (along with more free-flowing exhaust) onto the 210hp version of the Renesis? If I have my facts straight, the 210hp version does not have the variable intake system, right? And you would probably have to remove all that stuff to bolt on a supercharger, right? So why not start out with a less expensive car that doesn't come with all the variable intake goodies you have to get rid of? Does the 210hp version come with a 6-speed tranny, or is that only reserved for the 250hp version?

I'm not very knowledgeable about superchargers, but I am a mechanical engineering student, so If you have answers to the above questions, go ahead and lay the technical stuff on me. I can handle it.

Another advantage to putting an SC on the 210 HP version is that since it has a lower rev limit, the SC setup will not have to be compromised as much to accomodate the relatively large rpm range.

As far as weight offset, I don't think that a simple setup would be a big issue, personally. For example, the Jackson Racing SC kit for the Miata weighs some 25 lbs, IIRC. Owners of that kit report that it does not affect balance at all (and it's a lighter car). Don't forget, you will have more of a weight shift than that between a full and a 1/4 tank of fuel.

Normally, a properly setup turbo kit weighs a bit more (turbo, manifold, IC, BOV, etc. etc.).

---jps

Well, a 4 port was used for Turbo2's while the 6 port was used for N/A 2nd gen FC RX-7s

I could imagine a larger 4port design for supercharged/boosted RENESIS's from the factory. But for the aftermarket, a solution has to be found for the 6 port, as that's what the majority will be in the US, at least.

As far as the aftermarket is concerned, wouldn't it be a big disadvantage to make a kit for the 210 HP version because of the auto tranny? Am I smoking crack, or do I remember reading somewhere that the auto tranny is not up to much more power than the stock 210?

no i think you have it the wrong way around. the torque converter couldn't handle the 9000rpm. so the stuck a lower rev limiter on it. less revs=less hp

and with less revs comes the need for smaller port area (less volumetric flow requirements) thus only 2 ports/rotor vice 3 in the 250. I thing the higher possible flow rates in the 6 port version will outweigh the benefits of greater simplicity of SC'ing the 4 port engine.

Originally posted by zoom44
no i think you have it the wrong way around. the torque converter couldn't handle the 9000rpm. so the stuck a lower rev limiter on it. less revs=less hp

Oh, that's right. I remember now....then to answer my own question, I must be smoking crack :)

Originally posted by RedRotaryRocket


Oh, that's right. I remember now....then to answer my own question, I must be smoking crack :)

just remember to put it down once in awhile and you'll be ok ;)

Why a roots type blower? With all that room in the front (when I pull out stock air box & emmisions stuff), a Vortech "S" type will flow better, and is more thermally efficent than a roots blower. Plus you can add a nice Front mount I/C and raise your boost threshold. I dont know as far as weight between the two units, but just use the bathroom & dont eat before you go to the track and you'll save 1/2 that.

Kyle Lancaster--Double Agent Salesman

A roots type blower would be ideal because it is a possitive displacement pump. It would provide good boost at all RPM's. The Vortech unit is a Centrifugal blower, and it will provide almost no boost until the RPM's get up there. The place where the RENESIS could use the most help is in the low end, if for nothing else, to just improve drivability. That is why we are talking about a Roots... The advantage to a centrifugal, is they are much simpler to build, and are therefore cheaper, and you take less of a bite in efficiency, because, like I already stated, at low RPM's (read, cruising) it is not really doing anything. Newer Roots blowers get around this disadvantage by having a vaccuum actuated bypass valve, so when cruising, they too are doing nothing.

Originally posted by CraziFuzzy
...at low RPM's (read, cruising) it is not really doing anything... With an engine with a higher rev limit, a centrifugal SC actually hurts performance at lower rpms. At that's regardless of whether you are cruising or at WOT. Check out dyno results of centrifugal SCs on an S2000, and you'll see what I mean (make sure you know what you're looking at as far as other peformance mods too).

And you can install an IC with a roots type SC. You just plumb it similarly to the centrifugal SC.

---jps

I think an Eaton 4th generation:

http://www.magnusonproducts.com/images/mp62sc.jpg

can fit here:

The dimensions are here:

http://www.magnusonproducts.com/images/mp62draw.jpg

Please note that the length of the neck can have a wide range.

-Mr. Wigggles

Ps. you can get a clean engine bay pick from: http://www.mazdausa.com/MusaWeb/rx8/images/gallery/rx8_images_32.jpg

How about the piping of the SC...? How are going to route the in-out tubes?

I think a eaton supercharger will work if you change the intake manfold or with a Paton centfuigal supercharger will work with the stock manfold. I don't quite know where to put a a eaton super charger would god perfer it to a centfuigal because of the nstant pressure and then use a bypass value like it is used by Jackson racing.

it seems like b/c of the cramped engine compartment in the rear of the engine bay, would a turbo setup be "easier" to install since it doesnt need to tap into the engine belts anywhere it could be mounted farther toward the front of the negine bay, within reason of course.

A turbo would not give us the low end torque that we are trying to achieve with the SC. There should be enough room back there for the blower.

Originally posted by CraziFuzzy
A turbo would not give us the low end torque that we are trying to achieve with the SC. That's a fallacy. There are differences in off-throttle response time, etc., but those depend on which turbo setup you decide to go with. If you go with a huge turbo for peak power, then it will take all day to spool up, and will be frustrating in street driving (and some forms of racing, for that matter). But if you size your turbo correctly, it will offer good low-end torque and quicker response than you'd expect.

Add to that the fact that you will not get as much low-rpm boost with an SC on the higher redline Renesis than you would with an engine that has say, a 6k redline, and the SC loses some of it's advantange. In the case of a centrifugal SC, performance at lower rpms will actually be worse.

At that point, it becomes a personal choice. How much power do you want to give up for throttle response (same question goes for turbo selection)? How much power do you want to give up for cost and installation ease? For what some people want, an SC will be a clearly better choice than a turbo, while for others, a turbo will run circles around an SC.

---jps

i like the ease of tunability of a turbo. I like having the option of adjusting the boost anytime i want without having to spend hours switching pulleys. I know it can be a much more expensive choice but nothing fun comes cheap.

Anyhow, this topic has been much argued before so i say base your choice on the sound! :D j/k, but seriously

Jackson Racing has had very good results with the VTEC engines in the Honda and Acura line up. They use an Eaton SC. The Prelude kit gets 40% more torque across the entire RPMs. I'm sure they'll come out with an RX-8 kit. It seems ideal for what the RX-8 is lacking and it's from a well respected company.

They've got Dyno charts on their web site:
http://www.jacksonracing.com

Jackson, while being very good at the design of they're systems, are NOT to great with customer service / relations. They make a very good SC kit using the Eaton M45 for the Ford 2.0L Zetec found in the Focus, but over many numerous emails and phone calls, they could not tell me why it wouldn't fit on a zx2. The only answer i was ever able to recieve from them was that it will only fit on the focus. Oddly enough, I have seen a couple zx2's with Eaton M45's AND intercoolers squeezed behind the Zetec. Even if it would take some modifications to squeeze it in there, I would have been willing to shell out the cash for their kit. But they're lack of information at the sales level really turned me off the idea.

I got to talk with one of the Mazda tech guys at the Rev It Up event here in SF. He had some part with the development of the RX-8 and is up on who is doing what with performance upgrades.

One really interesting thing that he mentioned is that MazdaSpeed is developing a hydraulic supercharger. This would get around the mechanical limitations of the traditional pulley driven setups and would allow for a lot of programmability of the boost to match the need.

I know this is a completely new kind of system, but it really wouldn't be that difficult to put one together from off the shelf components. You can utilize a traditional blower design, but simply run it off of a hydraulic motor. You can get hydraulic pumps for almost any need, and the stuff in the middle is common enough.

Honestly, the hardest part of designing a system is going to be the intake piping. The stock system is so complex, and with 6 intake ports, that are designed to kick in at different rev's, it will take a LOT of R&D to design a replacement system. The advantage of going ot the blower, is that it will keep the flat torque curve, but only if you can keep the programatically modified intake. Fortunately, with a positive pressure in the header, it makes tuned lengths less important, so I'm thinking that a simple air-box plenum with some butterfly valves for the individual ports will be acceptable... of course, it is starting to look like I will not end up with the resources / time to work on this... Some changes at work, so to speak... :/

Im new to the whole supercharger and turbo scene. I was just wondering if and when a supercharger comes out for the rx-8 will it lower engine life or have any other bad side effects. Im planning to go on a lot of long trips back and forth from college to my house. Also do u guys think mazda dealers will install the super or turbo for you, so the warranty wont get voided.


Sorry for the noob questions

there's been a lot, and i mean a LOT of discussion about it so far... considering the amount of info we have, the vast majority of which is purely speculation.

people have said a turbo will be difficult due to the exhaust manifolds...and that a supercharger isn't as good over all the revs, but with either option, the renesis has a 10:1 compression ratio...that doesn't leave a whole lot of room for boost =p

so, keep yer panties on. the car ain't even out yet and it'll be a good while before any kits come out, then you'll get a bunch of owner reviews and can decide for yourself.

Often times you will decrease the compression ratio with FI to give better reliability, and I would guess they would do that (by using different rotors) if they supercharged/turboed (sp?) the Renesis.

It is against Federal Law for a Dealer to refuse a warranty claim because an aftermarket product has been installed on your vehicle. If a warranty is denied, contact the Environmental Protection Agency (EPA) at (202) 260-2080 or www.epa.gov or the Federal Trade Commission (FTC) at (202) 326-3128 or www.ftc.gov. Additional information is available at the SEMA (Specialty Equipment Manufacturers Association) website www.sema.org.

However, a warranty claim can be denied if the aftermarket product caused the problem that prompted the claim. So if you turn up your boost to 80 lbs, and your apex seals shoot through your hood, the engine won't be covered. But, if you installed a super charger, and your brake master went south, they cannot deny the claim. There is a grey area, however, like if your tranny or rear end go out but the boost was set to normal, better hope you can debate well!

"Where there is a will, theres a way" an cliche that aftermarket tuners live by... they also get paid for it :)

ENGINE RESPONSE:

TURBOCHARGER
The Turbocharger does not reach its maximum efficiency range until high speed and airflows are achieved later in the vehicle acceleration event. The latest Turbochargers with variable geometry housings and ceramic turbines still take four times as long as a positive displacement Supercharger to produce maximum boost.

SUPERCHARGER
The Supercharger is continuously driven at full boost speed for the given engine speed. This offers almost immediate boost response which takes approximately 0.4 of a second to produce 50 KPA boost.


EFFICIENCY:

TURBOCHARGER
Turbocharger airflow delivery characteristics do not match the requirements of the internal combustion engine because of the volumetric efficiency versus speed difference. Turbochargers only display efficiency over a limited flow range. Turbo systems must be compromised to provide some low speed boost while matching high speed flow requirements. This usually requires wastegating which reduces maximum power.

SUPERCHARGER
The Supercharger exhibits an airflow delivery characteristics very close to the engine requirement. Thus, boost remains almost constant over the total speed range without wastegating or other compromising control systems.


NOISE AND DURABILITY:

TURBOCHARGER
With Turbos driven by exhaust gases turbine noise is nearly eliminated. Durability cycles are affected by the extreme temperatures that the turbine and housings are subjected to, leading to fatigue and inevitable failure.

SUPERCHARGER
Supercharger noise along with durability concerns have been the expressed reservations associated with automotive use. With improved designs and advanced materials noise levels have been reduced considerably with durability cycles proven well in excess that of Turbochargers.


LUBRICATION:

TURBOCHARGER
Turbochargers are subjected to extreme temperatures and in "shut down" situation the oil remaining in the turbine bearing sections will reach coking (burning) temperatures. The carbon build up in the engines lubricating system will accelerate the internal wear of the engine and add to the rapid deterioration of the oil.

SUPERCHARGER
Superchargers can be lubricated by self contained systems which without the extreme heats experienced by Turbochargers will last for periods well in excess of the engine lubricants.


AFTERCOOLING (INTERCOOLING):

TURBOCHARGER
Turbochargers again are subject to extreme temperatures and discharge temperatures need lowering through aftercoolers if high performance levels approaching that of Superchargers are to be reached.

SUPERCHARGER
Superchargers do not require aftercooling as outlet temperatures rarely exceed 140 degrees C.


DRIVEABILITY:

TURBOCHARGER
Unlike a direct coupled Supercharger, performance is only enhanced in proportion to turbine speed. Therefore performance at low speed is limited and a distinct pause is encountered under acceleration known commonly as Turbo lag.

SUPERCHARGER
Performance is obtained without sacrificing the practical and constant rate in which this torque is delivered. Towing and Off Road-4-Wheel Driving can benefit greatly from the increased torque at low speeds.


EXHAUST EMISSIONS:

TURBOCHARGER
Turbochargers can be tailored to meet emission levels at normal operating temperatures but suffer on cold starts. Contrary to the heat generated by a Turbo the exit gases are still low and on cold starts results in a longer catalytic light up time. This results in unacceptable levels of exhaust emissions at engine start up and legislation is slowly reducing the light up period available which will create problems for Turbochargers.

SUPERCHARGER
With legislation increasing pressure on automobile manufacturers to generate clean running engines Superchargers can easily be tailored to suit engine manufacturers emission designs.


VEHICLE MODIFICATIONS:

TURBOCHARGER
A Turbo becomes an integral part of the exhaust system, therefore requiring major modification to the standard exhaust. This also is the single limiting factor dictating its position in relation to the inlet manifold. Additional pipe-work can be required to reach air cleaners and inlet manifolds when mounted on the opposite side of the engine. If an aftercooler is incorporated the potential piping requirements can become impractical. Turbochargers fitted to some vehicles needs to be insultated with a heat-shield lagging to protect under-bonnet-components from the extreme temperature generated. Brake
master cylinders have been known to melt in a Turbocharged vehicle which raises other problems. Internal modifications are required in some cases such as compression modifications to accommodate the hot delivery air of the Turbocharger. Early opening of the exhaust valve will allow a high blow down pressure giving smaller engines more drive pressure from its exhaust but does sacrifice engine efficiency at cruise due to loss of full gas expansion.

SUPERCHARGER
A Supercharger need not change the physical configuration of a motor vehicle. A Supercharger is fitted where convenient by brackets and drive belt. Standard air cleaner and exhaust stay intact. No internal modifications to engines are required as the extra boost delivered is at a moderate temperature and which reduces the chance of detonation. No heat shielding is required for under-bonnet-components as again operating temperatures are low. No excessive plumbing required as Superchargers do not require aftercoolers and the unit can be mounted near the intake manifold requiring only a short discharge pipe.


MARKET TRENDS:

TURBOCHARGER
Manufacturers have worked with or around the inherent problems of Turbocharging in the pursuit of performance, economy and emission controls. Now with other options available Turbocharging is becoming less important to many vehicle manufacturers.

SUPERCHARGER
Supercharging is becoming more widely accepted by original equipment manufacturers and different forms of Supercharging are now appearing on new vehicles.


SUMMARY:

In the past Turbocharging has been an accepted means of increasing engine performance. Even with its inherent problems it was the most cost effective method of forced induction. Now with improved manufacturing techniques and high volume production Superchargers can now not only offer better performance and packaging characteristics but can also now be price competitive.

Performance is obtained without sacrificing the practical and constant rate in which this torque is delivered. Towing and Off Road-4-Wheel Driving can benefit greatly from the increased torque at low speeds.

That settles it for me. I was trying to figure out a way to haul a trailer while I off-road with my RX-8 ;)

I don't even like turbochargers due to their driveability characteristics but I just couldn't read this crap and be silent.

Originally posted by Supercharger
NOISE AND DURABILITY:

TURBOCHARGER
With Turbos driven by exhaust gases turbine noise is nearly eliminated. Durability cycles are affected by the extreme temperatures that the turbine and housings are subjected to, leading to fatigue and inevitable failure.

SUPERCHARGER
Supercharger noise along with durability concerns have been the expressed reservations associated with automotive use. With improved designs and advanced materials noise levels have been reduced considerably with durability cycles proven well in excess that of Turbochargers.
Where is your proof? Tons of turbo engines live for 100k's miles. A turbo will not thermally fatigue any more so than a freaking exhaust manifold on a supercharged car.

Originally posted by Supercharger
LUBRICATION:

TURBOCHARGER
Turbochargers are subjected to extreme temperatures and in "shut down" situation the oil remaining in the turbine bearing sections will reach coking (burning) temperatures. The carbon build up in the engines lubricating system will accelerate the internal wear of the engine and add to the rapid deterioration of the oil.

SUPERCHARGER
Superchargers can be lubricated by self contained systems which without the extreme heats experienced by Turbochargers will last for periods well in excess of the engine lubricants. .
Coking is not true anymore with water cooled turbos and higher quality oils.

Originally posted by Supercharger
AFTERCOOLING (INTERCOOLING):

TURBOCHARGER
Turbochargers again are subject to extreme temperatures and discharge temperatures need lowering through aftercoolers if high performance levels approaching that of Superchargers are to be reached.

SUPERCHARGER
Superchargers do not require aftercooling as outlet temperatures rarely exceed 140 degrees C..
In fact the opposite is true. At any boost pressure a centrifugal compressor is more thermally efficient than a Roots or a Lysholm. At 5 psi a turbo will heat the air less. At 10 psi, also. At 15 psi, also. And so on.

There is more BS but I am feeling too lazy to go into it.

I can't wait for a 6lb of boost supercharger kit to come out. That'll be enough for me.

At the same time, I think Supercharger here has clearly exaggerated the benefits to supercharging.

-Mr. Wigggles

Originally posted by babylou
In fact the opposite is true. At any boost pressure a centrifugal compressor is more thermally efficient than a Roots or a Lysholm. At 5 psi a turbo will heat the air less. At 10 psi, also. At 15 psi, also. And so on.

There is more BS but I am feeling too lazy to go into it. Exactly.

---jps

Originally posted by Supercharger


EFFICIENCY:

TURBOCHARGER
Turbocharger airflow delivery characteristics do not match the requirements of the internal combustion engine because of the volumetric efficiency versus speed difference. Turbochargers only display efficiency over a limited flow range. Turbo systems must be compromised to provide some low speed boost while matching high speed flow requirements. This usually requires wastegating which reduces maximum power.

SUPERCHARGER
The Supercharger exhibits an airflow delivery characteristics very close to the engine requirement. Thus, boost remains almost constant over the total speed range without wastegating or other compromising control systems.




Don/t forget, a supercharger is driven off of the crankshaft. At the top of the rev range a supercharger, depending on the type, can easily steal 50 bhp just to keep itself spinning. This is efficiency?

This discussion...hell argument, over which is better has been going on for decades. If you say that superchargers are more efficient over all, someone will say that they parasitically pull power off the engine to operate. If you say turbo's fail b/c they use the engine oil system i'll say they are fine if you throw on an oil cooler.

No matter what anyone says there's always gonna be a counter statement for the other. Would it surprise you if many people bought one over the other based solely on sound??? i bet about a quarter of people buy things in this way.

Personally i love turbo's. I just don't like the idea of another belt off the engine. But then again i love anything that can put over 100hp into an engine. Either way you dress it up you're looking at thousands of dollars.

Just b/c superchargers (may becoming) the accepted choice of forced induction does'nt mean they are better. Cars have been, and still are being turbo'd from the factory with literally just the manifold and turbo being the only parts to the system and driving for 100k+ miles.

You seem like your trying to sell superchargers or just love them :cool:

Originally posted by Supercharger
ENGINE RESPONSE:

TURBOCHARGER
The Turbocharger does not reach its maximum efficiency range until high speed and airflows are achieved later in the vehicle acceleration event. The latest Turbochargers with variable geometry housings and ceramic turbines still take four times as long as a positive displacement Supercharger to produce maximum boost.

SUPERCHARGER
The Supercharger is continuously driven at full boost speed for the given engine speed. This offers almost immediate boost response which takes approximately 0.4 of a second to produce 50 KPA boost.


this is exagerated. Yes superchargers response time is faster but can you honestly perceive the difference b/w .4 seconds and .16 seconds?? Depedning on the size of the turbo you can have full spool by 2500rpms. For most people the speed at rpms below this mark are irrelevant anyway...unless you're building a drag car.

ok my rant is over. Basically it comes down to PERSONAL PREFERRENCE and application.

no, there is superior system, but if i say Super's wrong, he'll pull something ELSE out of that magical hat of his!! LOL!! :D

Originally posted by OrangeBingo


Don/t forget, a supercharger is driven off of the crankshaft. At the top of the rev range a supercharger, depending on the type, can easily steal 50 bhp just to keep itself spinning. This is efficiency?

In my last post I dispelled BS and exagerrations of how superchargers are superior. Now I will do the opposite and dispel the exagerated 50 hp number above.

Modern street belt driven superchargers consume about 15-25 hp. Some high hp versions for V-8's may suck up 40 hp. 50 hp is an exagerration.

Also, the power to spin a turbo is not completely free. There are pumping losses the engine must endure to overcome the increased restriction of the turbine. Since a turbo is more efficient and since some of the energy to spin the turbo is actually free turbos usually have about 30% of the parasitic loss that a belt driven setup has.

Basically a belt driven supercharger that can pump enough air for 325 hp will have about 25 hp of pumping losses and have a crank output of 300 hp. A similar turbo system of 325 hp capacity will have a crank output of about 315 hp. So the difference in peak power is 15 hp. Remember, this is peak power only. At cruise (say 20 hp) the turbo will not be more efficient at all. The turbo will still have a small pumping loss will the supercharger will be bypassed and will only have about 0.3 hp of pumping losses.

Turbos suck, Superchargers blow

Originally posted by babylou: 50 hp is an exagerration.


Actually, it is much, much worse. It was a guess that I stated as a fact. Sorry. Although I bet a roots type blower could do it.

Just wondering out of the blue, but was there ever such an application where someone used a hybrid turbo\super charger? I was told it has been done but without good results. I was also told that done incorrectly the supercharger would just rob the turbocharger of its ability to boost. If you can get a setup like this to work imagine the possibilities. But then the whole setup would just be too heavy for practical applications.

Originally posted by Y&Y
Just wondering out of the blue, but was there ever such an application where someone used a hybrid turbo\super charger? I was told it has been done but without good results. I was also told that done incorrectly the supercharger would just rob the turbocharger of its ability to boost.

yeah, Lancia had that in some of their Delta rally cars from the 80's (butt-ass-ugly things), and i know for sure that HKS developed a "twin charger" system for the MkI MR2 (which had a supercharger, high power version)... just some random examples, i'm sure there have been other applications like this...

really, i don't see the point of having two things which do the same thing, where one works half the time, and the other doesn't... too much wieght, too many moving bits, too much cost... just make the freakin' engine bigger if you're that desparate!! :D

Yes hybrids have been built. However, instead of getting the best traits of both systems they seem to get the worst traits of both systems. Plus we are looking at an induction sytem that costs more than the rest of the engine.

Originally posted by OrangeBingo
Originally posted by babylou: 50 hp is an exagerration.


Actually, it is much, much worse. It was a guess that I stated as a fact. Sorry. Although I bet a roots type blower could do it.

Yes there are Roots blowers that can suck up 50 hp. Top Fuel drag cars have something like 500 hp parasitic drag. Of course I think they are pumping like 10,000 scfm whereas a 250 hp street car my be pumping 380 cfm.

The largest modern Roots blower, an Eaton M112, can pump about 660-680 scfm depending on boost pressure. At this flow rate the blower has between 28 hp (5 psi boost, maybe 5.3 l engine) and 44 hp (10 psi boost, say a 3.5 l engine) of losses. At this flow rate the engine output would be about 400 hp after parasitic losses.

Originally posted by wakeech


yeah, Lancia had that in some of their Delta rally cars from the 80's (butt-ass-ugly things), and i know for sure that HKS developed a "twin charger" system for the MkI MR2 (which had a supercharger, high power version)... just some random examples, i'm sure there have been other applications like this...

really, i don't see the point of having two things which do the same thing, where one works half the time, and the other doesn't... too much wieght, too many moving bits, too much cost... just make the freakin' engine bigger if you're that desparate!! :D

i agree...the only application where a duel charger (turbo) system should even be used is in deisel big rigs. Since the deisel market drives the turbo industry they are now designing a twin turbo setup where, after the second turbo, total output is b/w 100-120 psi!!!! Did you know most big rigs rev limit to 2500rpms but have up to 17 forward gears?!?!?

Check the April '03 issue of Turbo & High Tech Performance magazine (www.turbomagazine.com). They have an article about "Compound forced induction" as they call it.

From the article:

Roots Advantages
-Instant boost on throttle application
-Good low-rpm boost (with by-pass valve) zero charge heating at idle and high vaccum cruise
-Good and linear volumetric efficiency

Roots Disadvantages
-Excessive heating at higher boost (over 8-10 psi) due to reversion-pulsed turbulence of non-compressed air from the supercharger encountering higher-pressure previously compressed air in the intake
-May be inconvenient or impossible to intercool
-Robs some of the power it produces from the crankshaft
-Can be noisy

Turbocharger Advantages
-Excellent thermal efficiency to high-boost pressures
-Not limited to crankshaft speed (may lag behing, but can surge ahead with sufficient exhaust energy)

Turbo disadvantages
-At least minimal delay in onset of boost
-Boost inaccessible at lowest rpm ranges

Compound Advantages
-All of the above
-Supercharger produces excellent low-rpm exhaust energy to spool turbo

Compound Disadvantages
-May be inconvenient or impossible to intercool supercharger section


Other info I could pull out:

"the turbo began making additional boost and torque above and beyond that of the supercharger as low as 2300 rpm. From this point, torque and boost increased in a smooth linear fashion until the wastegate opened"


So it seems they have a succesful application of combined forced induction.

EDIT: The engine they are working on is a 1MZ-FE 3.0L Toyota V6 (into a '91 MR2) with a TRD Eaton Supercharger @ 5 psi and a Majestic T-76 Turbo @ 5 psi for a total compounded 10 psi boost.

neit,

Very informative post. Thank you very much.

I agree completely with Turbo's Super/Turbocharger rundown and it is nice to know that someone has successfully implemented a "compound" system. (I bet it is pricey though)

-Mr. Wigggles

Hey, I was just looking in the turbo magazine web page and saw a twin turbo 350Z!!

"The tight confines of the 350 engine bay meant the hairdryers would have to be dropped out of sight"

"We took the tuning very slow because of the V6's high compression of 10.3:1. Little by little, the car began to run better and better. We finally figured about 5.6 psi should be within a safe limit through the factory catalytic converters, while still making a big punch in the power department.

Set at the aforementioned conservative 5.6 psi, the GReddy turbo kit dished out the power. The 350Z baselined at 244.4 whp on Dynamic Autosports' Dynojet. With boost coursing through the V6, output jumped to 334.2, an 89.8-whp gain through the cats in CARB-legal trim."


Final numbers:
Power 334.2 whp
Torque 339.2

MY Observations / thoughts:

It was possible to twin turbo it even with "the tight confines of the 350 engine bay" so it may be possible to turbo the 8

Also note that the engine has a 10.3:1 compression ratio, a little bit higher than that of the 8 (10:1) so it may be possible to have a little bit higher boost (maybe 6 or 7psi ?)

They achieved almost 90whp gain @ 5.6psi! I don't know how rotaries respond to boost compared to a piston engine so I can only imagine the power gains we can get...

Last thing, they acheived this using the factory cats in CARB-legal trim, imagine using some aftermarket high flow cats

Originally posted by neit_jnf
They achieved almost 90whp gain @ 5.6psi! I don't know how rotaries respond to boost compared to a piston engine so I can only imagine the power gains we can get...

well, that low boost pressure number is a good thing, meaning they're getting terrific flow with less effort from the turbo... boost pressure isn't a measurement of flow, just (obviously) how much specific force the turbo is putting on the air (pressure)... another thing to consider is that it's 3.5L large, which is a big big displacement... even if the efficiencies of the system weren't so good, you're still going to see huge quantitative increases in power with small increases in boost, simply because it's ingesting so much of it at once.

yeah that's the greddy Z. SCC has an article in the most recent edition on this, however i do beleive their dyno run only netted in the ~320 range. Which is still great. This is actually the first aftermarket twin turbo job i've seen since the rx-7 that actually gave great posistive results. Now all they have to do is gut that sucker and it'll be nice and fast.

EDIT: I'm really impressed they were able to safely setup the turbo's in a V6 environment

here, kidmarc (welcome friend) posted this in the Tech Garage, i just had to C+P it :)

Originally Posted by kidmarc
This post is late due to not reading this forum for a few months.

One pioneer in the turbocharging field is Allan Nimmo of Performance Techniques. He has demonstrated the hidden capabilities of the turbo many times. His work is well known in the world land speed records at Bonneville.

He was in Turbo and High Performance magazine in 1990 with a feature article on his turbocharged V-8 driven Mazda Rx-7 of 936 hp that posted 9.63 quarter mile times; 0-60 in 3.6; top speed 232 mph; lays scratch in all three gears; is an automatic; and all of this while the A/C is on. It is unnoticeable that the car is modified except for the low profile.

To note, Allan is a fan of the rotary.

To address whether to turbocharge, supercharge, or naturally aspirate... The choice comes down to the pluses and minuses. Contrary to Supercharger's comments, these (http://www.babcox.com/editorial/us/us99814.htm) are the issues as to turbochargers vs. superchargers/blowers

The minuses can be reduced once you understand some basics outside of automotive design.

Peace
marcus


for those that missed the link, i suggest you check it out here:

http://www.babcox.com/editorial/us/us99814.htm

Having lived with a twin turbo RX-7 already, should I choose FI, I'd definitely go with a supercharger this time around. IMO, the problem with turbo are several:

1) They run hotter than superchargers, creating backpressure into the engine. Not only is the extra heat hard on reliability to everything under the hood, but it's also harder on the cat system (my FD melted and clogged). I saw over 1400 degrees on that car without trying too hard...
2) Boost is not linear to throttle, you can get used to it, but it's not as easy to drive at the limit
3) Should the wastegate be insufficiently sized, dangerous boost creep can occur on some days (cold ambient) and not others.

Personally, I'd love to see a 75 hp self-oiling centrifugal supercharger kit running 5 psi, hence no real need for intercooling. Packaging would be easier, overall kit would be light, parasitic drag would be minimal, running temps (although higher due to horsepower) would be reasonable, and throttle-to-power output would also be direct. Sure, there wouldn't be gobs of low-end torque, but I much prefer playing in the mid-high end powerband anyway.

Originally posted by FritzMan
2) Boost is not linear to throttle, you can get used to it, but it's not as easy to drive at the limit
3) Should the wastegate be insufficiently sized, dangerous boost creep can occur on some days (cold ambient) and not others.


boost with a supercharger isn't linear with the throttle, and in fact is not throttle dependant at all (unlike a turbo): boost in a supercharger is entirely rpm dependant.

...an improperly sized wastegate is only the fault of the idiot that chose one that's too small, it's not a downfall of the turbocharging system.

Technically, you're correct in the sense that 50% more throttle doesn't give you 50% more RPM. However, it does become close to linear-like at higher RPM - and is still much more linear in delivery than a turbo which has a more variable RPM, throttle, boost relationship. Regardless of throttle, X RPM always delivers X boost on a supercharger, not so on a turbo.

That leads to another supercharger advantage, full boost in the lower gears. Typical turbo cars don't see full boost until 3rd gear when time and engine load are signicant enough to deliver it's full potential.

"...an improperly sized wastegate is only the fault of the idiot that chose one that's too small, it's not a downfall of the turbocharging system."

- hope you're not saying Mazda engineers are idiots!!! :) Cuz it's their design (FD) which used to overboost 100% OEM. Granted, it would be -20 outside (I drove the car year round) so I'm sure their engineers didn't figure someone would be driving a sports car in that temp. The super cool air would create a better burn to the rich mix making more exhaust than what the FD could handle. I do agree wastegates should be properly sized in the first place, but as I've shown it's difficult to anticipate all possiblilties. IMO, the dependency on a wastegate is a little scary, although they are reliable, I had a pop-off valve fitted to my car. With a supercharger the only way to overboost is to over rev.

Originally posted by FritzMan

- hope you're not saying Mazda engineers are idiots!!!

...they WERE the ones who tried too hard on the TT system for the FD.

Originally posted by FritzMan
Regardless of throttle, X RPM always delivers X boost on a supercharger.....

Not true. If this was true then there would be no need for a throttle. It would also make it impossible to "cruise". I can see it already. At 80 mph the engine must turn 4,000 rpm, the car requires 16 hp to overcome losses but at 4,000 rpm the engine builds 10 psi boost and 160 hp. Since the throttle is useless there is no way to match engine power to required power. I guess we will have to turn on and off the engine periodically like they did in WW1 radial engined aircraft.

Not quite sure I'm following you here. Centrigular superchagers are forced to generate a specific boost for specific RPM due to the non variable direct connection to the engine (belt). Actual boost used by the powerplant is dictated by how much the engine is capable of ingesting at a given time (ie: throttle opening). Excess boost is bled off or recirculated into the system (FD blow-off valve bled back into the airbox). So cruising is possible by simply bleeding off the excess (kind of like a intake charge wastegate). It's a bit of a waste of horsepower really because parasitic drag had occurred to build that boost which could easily be thrown away. Most manufactuers have gotten around the problem of wasting power when boost is not needed by having a vacuum activated switch to free-wheel the supercharger's pulley until power is needed. Hence, engines can switch between normally aspirated and pressurized.

i think mr.supercharger is partial to superchargers... I personally would go turbocharger because it dont want boost at low rpms, and with boost at high rpms it is mainly for race application. however I firmly believe that the installation of a forced induction system as well as the quality of its design and performance should be the main concern

This just came across my mind about turbocharging the RENESIS, and I think it's probably been speculated and tested by Mazda engineers.

Previously, rotaries are fantastic for turbos since the exhaust from the peripheral exhaust ports hit the turbine almost head-on (depending on the manifold, of course). Now with the side exhaust ports, the gas has to take a more convoluted path which takes away the advantages of an older turbo motor. This doesn't mean that can't turbo the motor, but it won't be as effective as before. Also, the peripheral ports also allow the use of huge A/R ratios (big high-end power) on the turbine without much ill effect. On the other hand, you don't have any overlap with the RENESIS, which is bad for turbos.

IMO, I think it would be more beneficial to go with a larger displacement 2-rotor in the future. No doubt you lose the tunability of forced induction, but you gain needed low-end power and keep the simplicity and reliablity of a non-turbo rotary.

Originally posted by Ahura
Now with the side exhaust ports, the gas has to take a more convoluted path which takes away the advantages of an older turbo motor. This doesn't mean that can't turbo the motor, but it won't be as effective as before. Also, the peripheral ports also allow the use of huge A/R ratios (big high-end power) on the turbine without much ill effect. On the other hand, you don't have any overlap with the RENESIS, which is bad for turbos.

IMO, I think it would be more beneficial to go with a larger displacement 2-rotor in the future. No doubt you lose the tunability of forced induction, but you gain needed low-end power and keep the simplicity and reliablity of a non-turbo rotary.

...side exhaust ports coming out into a turbo is still less convoluted than flowing in and out of a head (on a piston engine), or at least comparable (not worse).

A/R ratios have the same effect whether you have a P-port exhaust or not... RX-7 guys just like to think that because they port out their engine a LOT that the turbo spools faster (without a shred of quantitative analysis to prove this).

overlap is actually very bad for turbos, as with the high-pressure nature of hte system, you can end up with a lot of reversion (that means gasses flowing the wrong way) or a lot of charge flowing out the exhaust (just as bad for power as it is for emissions). what's actually bad for the turbos in the RENESIS is the long-duration intake cycle in the 6p motors.

:D yes. more displacement is better than less.

Originally posted by Efini 8
i think mr.supercharger is partial to superchargers... I personally would go turbocharger because it dont want boost at low rpms, and with boost at high rpms it is mainly for race application. however I firmly believe that the installation of a forced induction system as well as the quality of its design and performance should be the main concern

So does that mean I shoud refer to you as "Mr. turbocharger" then? ;)

Don't know if I was being referred to here or not, but just so you know, I'm not a die-hard SC fan or anything. In fact, I've never driven a centrifugally charged vehicle. I'm simply posting the facts as I see them. As my previous posting stated, I've done turbo (and lived with it's woes) so I'd like to try SC. Who knows, maybe there's an equivalent list of problems with that setup... IMO, for my fictious application of 325-350 hp and some improved low-end I think SC would be fun to try. If someone were to ask me to the best way to make massive power, then by all means, turbo it is.

Originally posted by FritzMan


So does that mean I shoud refer to you as "Mr. turbocharger" then? ;)

Don't know if I was being referred to here or not, but just so you know, I'm not a die-hard SC fan or anything. In fact, I've never driven a centrifugally charged vehicle. I'm simply posting the facts as I see them. As my previous posting stated, I've done turbo (and lived with it's woes) so I'd like to try SC. Who knows, maybe there's an equivalent list of problems with that setup... IMO, for my fictious application of 325-350 hp and some improved low-end I think SC would be fun to try. If someone were to ask me to the best way to make massive power, then by all means, turbo it is.

sorry I didnt mean any disrespect, I just thought your post was a little biast toward superchargers.

Turbo and rotary is not a good combination for a road car. Racing cars are a different story.

JSG confirmed that the engine bay is already very hot without turbo. Just think how much hotter it will get with a turbo. You won't be able to open the hood.

Originally posted by fritts
My thought on this is that the entire runner system will have to be eliminated for FI. Not to mention the dual throttle bodies. With the torque FI would add the variable exhaust length will not be needed.

give them time and show them their demand

http://www.pes-tuning.com/oldsite/Images/g2_kit_installed.jpg

they made aux s/c for the v6 A4 before, and eventually, remade the intake runners and making the whole system much more compact and efficient

i have no idea how or where they'll put one for the 8

they might go with a centrifigual s/c which is as compact as a turbo but doesn't have the lag of a turbo (a la spoon race s2k)

http://www.imagestation.com/picture/sraid65/pa8ea58f0ebe7abb032ea85a5a4ea4f42/fbf6577c.jpg

http://www.miataforum.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=11&t=012506

http://www.rx8forum.com/showthread.php?s=&threadid=4948

If you'd like to keep the intake manifold stock, then there really isn't much room at all.
The intake manifold is bigger since the intake tracts run wider to have a smooth curved shape instead of the traditional sharp bend on the bottom of the LIM.

I can see a small turbo being placed somewhere near the front passenger side wheel well, but the manifold design would be complex for it to be efficient.

We'll see what the aftermarket folks have for the RX-8 soon.

J

Originally posted by wakeech


...side exhaust ports coming out into a turbo is still less convoluted than flowing in and out of a head (on a piston engine), or at least comparable (not worse).

A/R ratios have the same effect whether you have a P-port exhaust or not... RX-7 guys just like to think that because they port out their engine a LOT that the turbo spools faster (without a shred of quantitative analysis to prove this).

overlap is actually very bad for turbos, as with the high-pressure nature of hte system, you can end up with a lot of reversion (that means gasses flowing the wrong way) or a lot of charge flowing out the exhaust (just as bad for power as it is for emissions). what's actually bad for the turbos in the RENESIS is the long-duration intake cycle in the 6p motors.

:D yes. more displacement is better than less.

Actually, the turbo does spool quicker when the exhaust is ported on the 13B. The earlier opening of the exhaust lets more unburned fuel escape which helps the turbo to boost higher and quicker.
As for the renesis, the exhaust pulses don't have the same kinetic energy as the earlier p-port motors and the temp is also lower making it a better candidate for supercharging.

ok I have seen the rumors in several car magazines such as Sports Compact Car, etc. that report Mazdaspeed is developing a turbo kit for the RX-8. Also many people are speculating on the boards about the possibility of a forced induction system.

I have confirmed with Mazdaspeed that they are not currently developing a turbo kit. If they do decide to develop one, much r&d is going to be required. The turbo most likely will be prototyped on a Mazda race car in Japan first - maybe the JGTC? That is just an educated guess.

However, this is what Mazdaspeed knows about the capabilities of F.I. on the Renesis:

- Can Handle Minimal Boost Pressures (5 psi or so)
Compression Ratio for RX-8 is 10.0:1

- Mazdaspeed is heavily studying and working with the Renesis as well as the RX-8. Performance is in mind.

- Mazdaspeed is working along side other companies to develop certain parts.

Again, the Mazdaspeed TURBO KIT is just speculation and nothing but a rumor. I just wanted to clear this all up. They might decide later to build one, but according to the my sources, they are not actively pursuing a F.I. solution currently.

Originally posted by Efini 8

...

Again, the Mazdaspeed TURBO KIT is just speculation and nothing but a rumor. I just wanted to clear this all up. They might decide later to build one, but according to the my sources, they are not actively pursuing a F.I. solution currently.

They are not actively pursuing a turbo or not actively pursuing FI in general?

Details in a UK magazine on the future RX-7 say that the next gen will produce around 300bhp using a modified Renesis platform (wider rotors, increased capacity to 1.6l) ....

If that's the case, then I wouldn't be surprised if they use that to form the basis of the MPS RX-8?


-andy-

Originally posted by sixspeed
Details in a UK magazine on the future RX-7 say that the next gen will produce around 300bhp using a modified Renesis platform (wider rotors, increased capacity to 1.6l) ....

If that's the case, then I wouldn't be surprised if they use that to form the basis of the MPS RX-8? Well, we do expect the MPS RX8 to share a bunch of things with a possible upcoming RX7. Engine upgrades (we do know that 300 hp was a goal, we don't know the method), possible SMT (we know that they were at least working on that), etc.

---jps

My Mazda guy here in Japan is quite hooked up, if he doesnt know he will spend a week trying to find out hehe.

SOOOOOOO i will ask if there is any info flying around, or just BS

JT

Originally posted by Dont_be_a_Rikki
10.0:1 Compression can be dealt with:eek:

water spray, 12:1 fuel maps :eek:, big ass IC's, and race gas/xylene rich :D

Originally posted by wakeech


water spray, 12:1 fuel maps :eek:, big ass IC's, and race gas/xylene rich :D

It's already been done on the 350Z (10.1:1 compression) @ 5.5 psi, no water spray, pump gas... yes on the big a$$ IC and don't know about the fuel maps.

Originally posted by neit_jnf


It's already been done on the 350Z (10.1:1 compression) @ 5.5 psi, no water spray, pump gas... yes on the big a$$ IC and don't know about the fuel maps.

:p c'mon, if you're gonna do it at all, do it right... 5.5psi is almost a waste of time... why not just go all motor?? if i'm gonna boost the motor, i'd spend the money and do it right.

i'm not raggin on you at all, but i personally think it's a pretty stupid thing how tuners like Greddy make this wimpy little kits for a ton of money that offer so little in increased performance when there are other solutions about... it's almost putting a turbo on your car just to say it's a turbo. poseurism. :mad: don't like it.

i sincerely hope that Rikki & Co. go all out and make something serious for the peoples...

keech - Id guess for a lot of people it's probably that indecisiveness caught in what you want to do with a daily driver...but I'm with ya, if I was wary like that, I'd stay away from FI altogether if I was going to get the 'boost' of an eBay electronic supercharger in the end :D

Some people just want to hear that BOV no matter what..

no point in paying $4000 for turbo kit that only boosts 5.5 psi - that is lame. our compression ratio is not that hard to work with, but it will take some long hours of r&d.

isnt the rotary's lack of engine tempature tolerance a bad combination with a turbo? shoulds like a mistake to me
i think you guys are better off looking for NA solutions or just waiting for the rx7

Originally posted by DijabutiA
isnt the rotary's lack of engine tempature tolerance a bad combination with a turbo? shoulds like a mistake to me
i think you guys are better off looking for NA solutions or just waiting for the rx7 You're way off. The rotaries handle the heat fine (thankfully so, because they create enough of it). The reputation of issues with high underhood heat comes from the 10s of rubber vacuum hoses associated with the sequential twin-turbo setup of the FD RX7. They would fail due to the extra heat, and were very difficult to troubleshoot.

---jps

Originally posted by wakeech


:p c'mon, if you're gonna do it at all, do it right... 5.5psi is almost a waste of time... why not just go all motor?? if i'm gonna boost the motor, i'd spend the money and do it right.

i'm not raggin on you at all, but i personally think it's a pretty stupid thing how tuners like Greddy make this wimpy little kits for a ton of money that offer so little in increased performance when there are other solutions about... it's almost putting a turbo on your car just to say it's a turbo. poseurism. :mad: don't like it.

i sincerely hope that Rikki & Co. go all out and make something serious for the peoples...

my FC TII RX-7 runs at 6 psi stock. did mazda waste their time boosting the '86 FC, pushing power up 40 hp to 186 hp? nope, these cars still blow the doors off new cars, mine does so reguarly :D

and there is no reason mazda can't simply add lower compression rotors to the renesis when turbocharging, that's what they did with the FC

I had a FC TII years ago, I remember it running at something like 8.5 psi stock. Maybe my memory is fading.

If I was to use forced induction in the 8, I would like to see around 10-12psi capability.

It's not only about boost pressure but air volume flow as well. The Greedy 350Z turbo kit @5.5 psi surely moves lots of air since they got a 90 whp gain with it, using stock exhaust.

By the way, I don't have a Z or plan on getting one or have any connections with Greedy. I'm just saying that a turbo kit when done right can have lots of power gains even at lowish boost pressure levels thus helping with durability and reliability.

I can't wait to see a bolt on turbo kit for the 8!! :D

Originally posted by neit_jnf
It's not only about boost pressure but air volume flow as well. The Greedy 350Z turbo kit @5.5 psi surely moves lots of air since they got a 90 whp gain with it, using stock exhaust.

the gain in power is big because it gives the VQ some legs in the upper end, and it's three-and-a-half friggin' litres of engine ("gi-normous" i believe is the correct term), obviously there's going to be some serious torque gains for a small increase in charge density.

the total amount of air you're crushing in, which is best measured by mass (like kg/cc or whatever). the exhaust couldn't have been "stock" otherwise they'd never be able to throw a turbo in there. if you mean from the cat-back it was stock, that's a different story, but it's not stock.

i did write a reply to the post about the TII only having a handful of psi of boost, but it got killed by the server, and it was 12.30am... i didn't want to retype it, so i will now:

the reason that Mazda only put a little bit of boost on the TII's, or really why any manufacturer only puts "a little" boost on anything, is becuase they had to make it clean, economic, drivable, and CHEAP (for enhanced profitability, which is the name of the game).

when a tuner goes to the trouble and cost of changing their car, enhancing some characteristics over others (this case being power), they're quite willing to forego some if not all other attributes for one at (sometimes) a considerable cost. this is why i say spending several THOUSAND dollars for a measly 5.5psi is stupid, where you could spend another thousand or two on top of that, and end up with a much better motor in the end.

in any case, i just dislike "complete" or "comprehensive" kits... to do it right, you gotta do it yourself (or at least know what's being done).

Originally posted by rx7aggie
there is no reason mazda can't simply add lower compression rotors to the renesis when turbocharging, that's what they did with the FC

one word: cost.

now, i really dont' believe that'll stop them if they're going to make MPS engines turboed from the factory (probably not), but for a kit for RX-8's that're already being made, how is Mazda going to put 9.0 rotors in them??

this supposed kit we're talking about is one for the aftermarket, meaning that unless you're going to rebuild the engine completely to then build it up more (in which case there's no way you're going to buy some kit for the build up).

I was under the impression that the Rx-8 was only 9.2:1 compression ratio? I am looking now for where i read that but i will be back to be for sure.

I'll be dammed, nope its 10:1 sorry i appoligize

also you have to consider comparing the greddy 350z turbo kit is that they also used electronic management with various electronics and also have bolt on modifications, surely they can do better than that. Power a company in Japan has already made a considerable twin turbo kit that surpasses Greddy's performance gain figures. Which goes to show, many companies choose to go different directions in which they think people will buy. Greddy typically makes bolt on kits which do not require much tuning, they aim for the DIYers that are not too familiar with the technical aspects of turbocharging a vehicle. Simply said, I believe I would spend my money on the most bang for my buck. There is still hope though...

I have read a lot about it, but have not seen/heard any evidence of it actually happening as yet.

Be great if someone knows out there?

i own a rx7 twin turbo and i will never get a turbo car again .only if i win lotto or make more money because if you guys didn't know is alot of work to keep a turbo car running perfect. better of with a supercharger . i have a millenia s and never had a problem with it .

Originally posted by Red Devil
I had a FC TII years ago, I remember it running at something like 8.5 psi stock. Maybe my memory is fading.

If I was to use forced induction in the 8, I would like to see around 10-12psi capability.

6.56 psi on a stock S4, ~8.25 psi on a stock S5

Originally posted by j-apex rx
i own a rx7 twin turbo and i will never get a turbo car again .only if i win lotto or make more money because if you guys didn't know is alot of work to keep a turbo car running perfect. better of with a supercharger . i have a millenia s and never had a problem with it .

it runs off the miller cycle, NOT the otto cycle. the intake valves remain open during part of the compression cycle. you cannot compare a miller cycle supercharged piston engine to a sequential twin-turbo otto cycle rotary engine!

that's like comparing deseil to a two-stoke otto cycle.

I'll put it this way - somewhere in Japan someone is feverishly working on one. Japanese *LOVE* turbos, and they love the RX-8. It's just a matter of time.

One thing that's weird for the Japanese - domestically, the RX-8 is the first non-turbo rotary since the 1st gen RX-7, and even then they had a turbo 1st gen at the end of the production run. All 2nd gens sold in Japan were turbo, as were 3rd gens, as was the Cosmo.

I also wouldn't doubt that HKS and/or Greddy will come out with a conservative turbo kit at some point.

Dale

Originally posted by dcfc3s
All 2nd gens sold in Japan were turbo

Dale

wow, really?? neato. i s'pose that's why there're so many JDM engines available for cheap.

Originally posted by Dont_be_a_Rikki
here:p .


-Ryan

"here" meaning Peter Farrel Supercars. ;)

Originally posted by wakeech


wow, really?? neato. i s'pose that's why there're so many JDM engines available for cheap.

Yep. Takes some people time to get their heads around that...:)

It's funny - in the US, the 2nd gen turbo was fully loaded - power everything, nice 16" wheels, nice stereo, you name it. In Japan, since all cars were turbo, they had a turbo base model. I've got an '87 Japanese dealer brochure (took me a while to get my hands on that sucker! :)) that outlines all the models.

The base was the GT. Steel wheels, no hubcaps, no sunroof, cheap seats, crank windows, manual mirrors, you name it. SUPER basic. But, it did have a turbo :).

Anyhow, getting WAY off topic...

Speaking of, I remember watching an Option video soon after the new Toyota MR-2 Spider was released. They were driving around in one with a Blitz turbo kit - that car was still way new at the time. There's probably other examples, but the Japanese aftermarket industry is *HUGE*. Just take a look at Eastmoon's group meeting photos - pretty much every RX-8 is modified at least a little. It's VERY hard to find a sport/sporty car in Japan used that isn't already modified at least a little - wheels and exhaust at least.

I predict that in one year, there will be at least 3 turbo kits available for the RX-8 in Japan. Some may or may not be over here or commonly available by that point, but they WILL be made, trust me :).

Dale

Originally posted by Dont_be_a_Rikki


Yup. But cant advertise or the mods we get all gay on me:cool:

-Rikki

Yup

Originally posted by dcfc3s
I'll put it this way - somewhere in Japan someone is feverishly working on one. Japanese *LOVE* turbos, and they love the RX-8. It's just a matter of time.

One thing that's weird for the Japanese - domestically, the RX-8 is the first non-turbo rotary since the 1st gen RX-7, and even then they had a turbo 1st gen at the end of the production run. All 2nd gens sold in Japan were turbo, as were 3rd gens, as was the Cosmo.

I also wouldn't doubt that HKS and/or Greddy will come out with a conservative turbo kit at some point.

Dale

Hey Americans *LOVE* turbos too!

Snails rule!

(Unless they happen to be working in a twin-sequential configuration with ~70 some odd vacuum hoses, restrictor pills, check valves, solenoids and other crap. ) :D

do u think that u wud be able to supercharge or turbocharge the 8? want feedbak!!!!!

You can supercharge or turbocharge any engine. Why not?

Either or. The rumormill says Mazda will FINALLY supercharge a rotary engine for the Mazdaspeed RX-8. I think supercharging's great as it enhances the rotary engine's power without adding throttle latency.

Turbocharging shouldn't be to big of a deal, but the exhaust manifold to drive the turbo will be tricky to fit as the engine's already in the transmission tunnel :)

okay...i have been researching most of the new import cars coming from japan and europe...first off everyone is trying to make cars built up as much as possible as an N/A...thats why the new M3 has such high compression and same with the 350z, rx-8 and other cars...unless it comes charged in some way its going to cost money to do such...the new greddy kit for the 350z is about 5k installed...for an extra 90hp....the problem is the high compression...now on the rx-8 the problem comes in as well it doesnt have a head gasket...cause if it did just get a thicker gasket for more boost...to boost the rx-8 to at least 1 bar well heck your better of buying an rx-7....i think we need to face the fact that there will never be super cars like the rx-7, supra, 300zx, or skyline again....thats why i might just settle for the new vw r32...awd, 6 speed and 300hp ...cant go wrong...cause after test driving the rx-8 i feel that new dodge sst or what ever might be faster

Originally posted by vaughnc
Either or. The rumormill says Mazda will FINALLY supercharge a rotary engine for the Mazdaspeed RX-8... The rumormill also says that Mazda will turbocharge the rotary for the Mazdaspeed RX-8, and it has said that it will be a simple increase in displacement.

---jps

Originally posted by crazydrifter
now on the rx-8 the problem comes in as well it doesnt have a head gasket...cause if it did just get a thicker gasket for more boost

To lower compression on a rotary you need to increase the size of the recession in the rotor. This will probably mean entirely new rotors.


my opinion is that a high compression/low boost turbo option is quite attractive for this kind of car. While you won't end up with as high a peak horsepower figure, you will retain good power off-boost and give yourself strong, linear power on-boost. much more in-line with this car's character.

Another supercharger vote here. No spooling up and much easier to manage

According to all the rumors, if you listen to them, is a 1.6L rotary engine in the works, intented for the future RX-7, as well as a 3-rotor variant of the RENESIS, as well as super and/or turbo charging the existing engine. Most of the people linking to the technical experts say that it's not going to last well with more than 5psi of boost.

5PSI should be enought for more torque and another ~25-45HP.

I'm sure someone's working on a Lemans type car with a 3-4 rotors as well.

BTW - would a 6 rotor lemans car suck too much gas or would it technically work?

I would love to see some pics or some other specs on a supercharged version of the 8!! Long Live The Rotary!!

Considering one doesn't exist yet, good luck :).

Dale

Saw some guy on the web talking about one with 575 hp and was just wondering... THANKS!!

Originally posted by dcfc3s
Considering one doesn't exist yet, good luck :).

Dale

Nope, Trust has an RX-8 with a TD06-18G mounted on it. 50HP gain for the TD06.

were still waiting for pics of that setup

Pics are above.. hehe

MikeB--You have to have a little faith man. I do what I can...

Thanks !!

thanks jt

Yep im waiting on eaton or yaw to start selling the bolt on

My guess is that turbos kill normal driving in these high rev high compression sports cars. Think about the Comptech S2000 that just won the Fourgasm C&D contest. The S2000 has no low end torque, wouldn't it benefit from a turbo instead of a supercharger?
The supercharger helps the engine where it isn't really needed, resulting in the spin or bog it characteristic all the magazines have claimed.
A turbo would make more sense, but that little engine doesn't create enough exhaust at low rpms to spin anything that could keep up with the engine when it kicks into it's atmospheric power band. A little turbo would now restrict the engine and it would actually lose HP.
They could put a big turbo on there but now you have some big fan blades slowing the car down at low rpms and the car is slow enough already down there.
The rotary is very similar, that's why the RX-7 (FD) had a sequential system. Small turbo for low RPMs and a big turbo for the upper band. However, this made the RX-7 very expensive and complicated.
A lot of people swap out their two turbos for one massive guy for serious top end power. But those cars lose their daily driving characteristics.
However, in the next couple of years we may see VATN ( I think that is right) turbos that can dynamically change their A/R ratio thus acting like a small turbo at low rpms, and a big one at high rpms. This would be a huge step for the automotive industry. It definitely isn't going to be here soon enough to wait on turboing your RX-8 though. Just properly size the turbo for your application. Compressor maps are beautiful thing.

dont forget tuning is a critical part of turboing a vehicle properly

Hi all,

If you can get a turbo into the engine bay (I still haven't seen any hard evidence from anyone actaully doing one yet?) then would the 4 port or 6 port be better for doing so.

Also, does anyone know how much more different the throttle body is on the 4 port engine to the 6 port? (I understand that the plennum is different for sure).

Serious replies only please (last thing I want is another messy thread!).

Here ya go -

http://www.rx8club.com/showthread.php?s=&threadid=9603

Greddy's already got a kit coming. I think pics of the prototype are on the 2nd page.

Anyhow, it's really hard to say which would be better - the 4-port or 6-port motor. You would probably want to change the port operation so they're fully open under boost. Time will tell there.

Dale

This is a sidebar regarding porting and the 4 and 6-port engines. In the past, most (if not all) folks recommended NOT porting the 6PI engines. That meant if you wanted bad-ass porting, you had to swap in a 4-port motor (or was it just the housings?). I would imagine we're in kind of the same boat with the RENESIS, unless someone got really smart about porting the tertiary ports (and modding the actuators). That could mean that the Standard Power RX-8 may have more N/A potential than the High Power. Would need upgraded fuel supply, I'm sure, as well as a tranny swap (or high(er)-stall torque converter) since all that new power will be at upper rpms.

*search*

the 4 port motor would be better.

The past 4 port engines have always flown more air than the 6 port engines on a flowbench. However the 6 port engines have still always been able to get very close to the power levels of the 4 port engines. First of all, the 6 port engines intake ports are open longer which allows more time for air to enter the engine. The small runners are poor for good flow though. Luckily there is a phenomenon that is a very good side effect of having several seperate ports. When the rotor turns and closes off the bottom port on the end housings, all of the remaining air is forced to flow into the engine through the small upper port and runner. This increased amount of air through the upper port causes it to speed up and charge more air into the chamber. It is all about velocity and not volume. Many RX-7 people make the huge mistake of combining these ports for added flow. The problem is that you kill the velocity that you get from them being seperate and power goes out the door even though it flows better. Go search the RX-7 forum for anything that says "monster port" or "siamesed ports", etc to see what not to do.

Either engine will respond very well to forced induction. I have turbocharged both types and gotten great results from both setups. On the RX-7's the 6 port actuators are in the way so it is easiest to just leave them open full time. Power falls off too hard below 4000 rpm and light loads. It isn't as nice for just driving around and gas mileage gets worse. Then again that could also be a side effect of staying on the gas more too. The plus side is that with all of the port area the turbo likes to spool faster. If I were to turbocharge a 6 port engine again, I would find a way to leave the port actuation alone. You really want to increase power across the board rather than at the expense of another area. The 4 port engines are still wonderful performers. All of the big high power RX-7's use 4 port engines although this is mostly due to the fact that it is this engine that came with turbos. The 4 port Renesis has a higher torque peak and it is lower in the rpm range. This means that power is slightly greater in this engine than in the 6 port up to about 7000 rpm or so. A turbo can overcome the top end deficiencies but it will boost the midrange much better. My choice for the street would be a turbocharged 4 port Renesis in a 6 speed car.

That's my .02

Originally posted by jdwk
My guess is that turbos kill normal driving in these high rev high compression sports cars. Think about the Comptech S2000 that just won the Fourgasm C&D contest. The S2000 has no low end torque, wouldn't it benefit from a turbo instead of a supercharger?
The supercharger helps the engine where it isn't really needed, resulting in the spin or bog it characteristic all the magazines have claimed.
A turbo would make more sense, but that little engine doesn't create enough exhaust at low rpms to spin anything that could keep up with the engine when it kicks into it's atmospheric power band. A little turbo would now restrict the engine and it would actually lose HP.
They could put a big turbo on there but now you have some big fan blades slowing the car down at low rpms and the car is slow enough already down there.
The rotary is very similar, that's why the RX-7 (FD) had a sequential system. Small turbo for low RPMs and a big turbo for the upper band. However, this made the RX-7 very expensive and complicated.
A lot of people swap out their two turbos for one massive guy for serious top end power. But those cars lose their daily driving characteristics.
However, in the next couple of years we may see VATN ( I think that is right) turbos that can dynamically change their A/R ratio thus acting like a small turbo at low rpms, and a big one at high rpms. This would be a huge step for the automotive industry. It definitely isn't going to be here soon enough to wait on turboing your RX-8 though. Just properly size the turbo for your application. Compressor maps are beautiful thing.

A well designed supercharger can give big gains across the rpms. Look at some of the Jackson Racing kits for cars like the Prelude. It gives a 40% increase across the rpms.

I think that for the RX8 a supercharger is the way to go. Since you're going to be limited on boost you might as well go with a low boost supercharger. It will be easier to maintain and easier to design. Forget the turbo because it's too many parts for too little of a gain.

Originally posted by AbusiveWombat


I think that for the RX8 a supercharger is the way to go. Since you're going to be limited on boost you might as well go with a low boost supercharger. It will be easier to maintain and easier to design. Forget the turbo because it's too many parts for too little of a gain.

Spoken like someone who hasn't driven a turbo rotary...:)

Rotaries and turbos get along together like peas and carrots. Part of the reason is rotaries have VERY powerful exhaust energy - I've read it's actually equivalent to a 12-cylinder engine! You can run a much bigger hotside and get far better flow characteristics with a rotary.

Put a T04-series turbo on a rotary, and it's a case of how much power you'd like to make. 300hp is easy. Just keep throwing fuel at it :).

Many turbine housings are divided, giving two exhaust paths around the turbine wheel to spin the turbine up. Run a divided manifold so each rotor has it's own path through the turbine, and you can run a much higher AR turbine with less lag and more flow.

Dale

Very true with the older rotaries. SUPPOSEDLY the Renesis doesn't have quite the exhaust energy of the previous models. I don't know how significant that is (or even if its really true, although given the added efficiency of the Renesis it makes sense).

jds

the reason I say supercharger is because with 10:1 compression you're already looking at ~5 PSI or around 50-60 hp. So for such a low boost application why burden your car with the added heat, intercooler, turbo, and all the piping rather than a simple belt and supercharger. It's less complex and thus more realiable.

I dont know much about turbochargers. I know they will void the warranty if you get one. I want to know if you get a turbocharger on the Rx8 will the gas mileage that isalready bad right now get even worse or stay the same?

It really depends on how you drive it. Under boost youll be eating gas like crazy, but while cruising or under light acceleration, you'll see about that same mileage.

from what I've since on this form the dealer must prove that the aftermarket piece you put on your car directly affecting what is not working to make the warranty void. For example if you lower it and then it starts leaking oil they still must fix that because you lowering it didn't cause the problem

a couple of months ago i kept on hearing about how renesis could "easily" put out 280 hp NA. now everyone is talking about FI, and talks of improving NA engine performance has gone down the drain. anyone know about any NA tuning they've been working on?

boosting N/A performance via the engine would maybe one would consider a 20B or 3 rotor rotary if you want to go with N/A and port that sucker. But if you are doing that why not go turbo cuz like others said, they work great together!

Also one point about supercharging vs. turbocharging is that supercharging is limited but with turbocharging the boost increase and rebuilding of the engine and fuel/timing adds sooo many more possibilities to high performance gain figures

How about taking the Twin-Turbo setup from the 7 and use it on the 8? That should work shouldn't it? Or would the 10 to 1 compression be a problem? I wouldn't think it would be, but I'm not in the know when it comes to this things - yet.

Originally posted by Rotary Soul
a couple of months ago i kept on hearing about how renesis could "easily" put out 280 hp NA... talks of improving NA engine performance has gone down the drain. anyone know about any NA tuning they've been working on?

i don't know who "they" you're thinking of, but since the 70's you can take a 13B block engine and make more than 300hp on it EASILY, zero turbos: it's called the Perhipheral Port (and ~10k RPM redline).
now that emissions and fuel consumption are high on the priority list, efficiency is traded for ability to make power at high rates of consumption.

to re-tune the engine to 100% top-end comprimise could see this motor to 280hp or more (at the crank), but in its factory guise it's (obviously) far more subdued, emissions friendly, and less thirsty (don't even start, it depends on how you drive it: ask Elara).

Originally posted by Efini8
boosting N/A performance via the engine would maybe one would consider a 20B or 3 rotor rotary if you want to go with N/A and port that sucker.

Also one point about supercharging vs. turbocharging is that supercharging is limited but with turbocharging the boost increase and rebuilding of the engine and fuel/timing adds sooo many more possibilities to high performance gain figures

"put a bigger engine in it"... typically American answer ;)
seriously though, tuning the engine as-is will result in pretty siginificant gains, especially as tuners test the (rumoured to be quite conservative) redline, and push porting further and further as a SCIENCE (and not the "make it as absolutely huge as possible" approach so favoured on forums like nopistons :p), and art.

when people get sick of whining about their lost 9hp and realize that 250 isn't all that much to brag about either (relative to many other cars on American roads today), and are ready to take the plunge, we (i'm hoping) will see the NA motors eclipse some previous RX-7 twin-rotor records.

as far as supercharging vs. turbo charging, PLEASE KEEP IT OUT OF THIS THREAD. there are already about a million on this server already. i'm pro-turbo, and have voiced my opinions on many technical concerns about both. search, read, revive and post. please.

Originally posted by Noxlupus
How about taking the Twin-Turbo setup from the 7 and use it on the 8? would the 10 to 1 compression be a problem?

the sequential twins setup on the 13B-REW was a seriously over-engineered peice of equipment for the series 7 RX-7's that made it to north America, and is the source of much of the wankel-phobia present in today's car market.

as a system, it's alright, but is completely unecessary as a system to try and develop a quick-spool, flat boosting system, possibly even at the time of its inception: twin-turbos in the late 80's and early 90's were almost completely a marketing tool. a slightly larger single turbo would have slightly (maybe even undecernably) longer spool-up time (turbo "lag" is determined by many things, and spool-up isn't the greatest factor either), but would remain far more efficient over a wider range of flow volumes and boost pressures. basically, if Mazda or MazdaSpeed is going to develop a supercharging system (by either belt or exhaust driven compressors), it'll be certainly using only a single, simple compressor setup.

Are you guys saying that it would be better to turbocharge the four speedsautomatic Rx8 instead of the six speed stickshift Rx8?? Are you just talking about something else?

Originally posted by JeRKy 8 Owner
Are you guys saying that it would be better to turbocharge the four speedsautomatic Rx8 instead of the six speed stickshift Rx8?? Are you just talking about something else?

no, we're specifically addressing only the engine side of the equation. North America is the only continent that gets automatic 4 port motors, whereas in Europe and Asia you can get a 5 speed with it.

i forget where the auto is scavanged from (pretty sure it's a Mazda unit...??), but should still be good to take the extra torque of a turbo.

In Asia we would be able to get the 5speed manual, I guess this would be the best engine to put a turbo in. Manual trans, 4 port engine.

Australia has the 4 port Auto also. I THINK? the UK is getting the 4 port engine (low power as it is known as) with the 5 speed manual, and the 6 port (high power) with the 6 speed manual. I don't believe that they are getting an auto version.

I will be close to doing either a turbo or a supercharged set-up myself in a few months time.

I know one thing for sure - there is a lot more room around the inlet manifold on the 4 port engine. So it would probably make supercharging easier - as for the turbo set-up the battery will have to go to the boot and the exhaust manifold would have to be quite long to bring it up and away from the oil metering pump etc. as there is no room along side the engine.

If I go down the supercharging route I would look at a mechanical type that provides boost at low rpm - still a little way of the decision yet.

.ps Next thing is - how strong is the Auto box? :eek:

Hey, new to the scene here...I'm debating picking up an 8...Been reading the forums, watching the problematic areas and resolves of the threads...although I havn't really seen much chatter about any means of future suppliers of forced induction for the 8's. I realize that some will say...you need to get an rx7 in that case...could be, but I was never a fan of the seven. Not really a fan of import anyway, but I have been following the progress of the 8 from the beginning and it is really an ingenious and technically sound project. I really like it... and am ...eer want to pick one up..but I was wondering if any of you know of any companies that are investing in a turbo kit for it?

I have had several boosted cars and it's a rush that doesn't go away once its there....from a 87 GNX, 67 gt350, turbo 302 mustang, and now a 00' Lightning...I just haven't really seen any threads for it and wanted to get an opinion from everyone here.....

BTW nice forum...format is simple and the color scheme is A+++

Thanks Guys
Steve

Welcome to the Forum! Although this car is very new, a lot of R&D is going on right now. I think that there are at least about 3 turbos in development. The ones that come to mind are greddy, SSR engineering, and Trust. I think that Apex may be developing one also, but this is just speculation. They just recently picked up they're guinea pig rx-8, :) so ive heard. There has also been many rumors about a mazdaspeed supercharger, made by eaton. Speculated #s are a boost of 20-30hp but a whopping 100+ lb/ft torque increase. Either way, any forced induction will be running 5-6 psi at the max so you wont be feeling that kick in the pants very much. All the kits should be running fairly small turbos which results in a very quick spool up in combination with the wonderful rotary engine. :D

any guess as to the effect of having a turbo in the 8? requiring shifting mroe quickly, not using the upper RPM's as much? I've never owned a FI car. Just trying to get a sense what it would be like.

I could definitely use extra torque, doing alot of stop and go, as I do in the city, but I really do enjoy driving in the upper RMP range of the 8 (of course when I'm not granny driving testing the MPG- which is often) I just wouldnt want to do anything to ruin that wonderful 7000 rpm and up feeling.

Emailist- it sounds like a supercharger would much better suit your situation. eaton superchargers are very fuel efficient and would provide loads more low end torque but a turbo produces a stronger mid- high end.

Originally posted by Shadygt2000

I have had several boosted cars and it's a rush that doesn't go away once its there....from a 87 GNX

color me impressed =) that car/motor is on my list of things to eventually tinker with

*can't believe what he's reading*

c'mon guys, read up on what your'e talking about before you start spouting bullcrap.

http://www.rx8forum.com/showthread.php?s=&threadid=8778&perpage=15&highlight=eaton%20supercharger&pagenumber=1

http://www.rx8forum.com/showthread.php?s=&threadid=9500

http://www.rx8forum.com/showthread.php?s=&threadid=9603

i did state that the numbers were rumor/speculation... and i do believe all the info i stated has been posted in the past

Its nice to know performance items are being made. So far i've seen a couple air intakes that are in development :D

Originally posted by SuperRex
i did state that the numbers were rumor/speculation... and i do believe all the info i stated has been posted in the past

those threads... haha... oh boy. i tried to find the actually good (and technical) mouldy oldie "turbo vs. supercharger", but couldn't find it... i hope it didn't get lost/deleted.

but those numbers (like thinking 6 psi is gonna hit another 100lbft of force at any rpm) are just a bunch of baloney, and aren't worthy of mention. if Mazdaspeed came out with any kit that ups low range horsepower trading off potential top end, i'd be disappointed (that said, i doubt that's what they'll do... Japanese hate blowers, and love turbos... for good reason).

finally, most of the stuff on this board is whining, repeated questions answered repeatedly, and speculation. sometimes, a few of the bright guys from the early days would get together an answer a few big questions, but now it seems to be the same old thing... over and over and over. just 'cause it was posted here before doesn't mean it was true, and sometimes not even worth mentioning again.

Originally posted by wakeech

but those numbers (like thinking 6 psi is gonna hit another 100lbft of force at any rpm) are just a bunch of baloney, and aren't worthy of mention. if Mazdaspeed came out with any kit that ups low range horsepower trading off potential top end, i'd be disappointed (that said, i doubt that's what they'll do... Japanese hate blowers, and love turbos... for good reason).


I stand corrected!:D I've known that 6 psi out of turbo would never produce those #s anywhere but I don't know much about blowers and have heard of massive torque increases from them in the past so i just assumed it was possible. I apologize for posting old rumors and will refrain from doing it again.

PS here are a couple old turbo vs super threads ;)
http://www.rx8forum.com/showthread.php?s=&threadid=5822&highlight=turbo+supercharger

http://www.rx8forum.com/showthread.php?s=&threadid=3707

Originally posted by SuperRex
PS here are a couple old turbo vs super threads ;)

...yeah, i was searching before i even first posted here... i still can't find the (actually good) one i was looking for.
those aren't bad, but there WAS another... can't friggin' remember... anyways, it was pretty good, layed it all down about how the 4 port motors are better for FI, and turbos are better than superchargers (while the supercharging guys put their hands over their ears singing "la la la").

http://www.jacksonracing.com/pages/faq.html#compare

Originally posted by wakeech


...yeah, i was searching before i even first posted here... i still can't find the (actually good) one i was looking for.
those aren't bad, but there WAS another... can't friggin' remember... anyways, it was pretty good, layed it all down about how the 4 port motors are better for FI, and turbos are better than superchargers (while the supercharging guys put their hands over their ears singing "la la la").

except for turbo lag.. but they are still better :O.

if i decide to turbo my car will i throw off the 50/50 weight ratio?

thanks for the link baron

no

no matter what you do to the car, if you decide to want to keep the balance even over all 4 tyres, you can always shift things around or selectively reduce weight to get things right.

but, if you mean to ask "will a turbo system make my engine heavier", yes it will. you can compensate for it, but it will.

Hello i just wanted to ad to your post i hope you guys dont mind a none RX PERSON POSTING the similarities. Both turbochargers and superchargers are called forced induction systems. They compress the air flowing into the engine The advantage of compressing the air is that it lets the engine stuff more air into a cylinder. More air means that more fuel can be stuffed in, too, so you get more power from each explosion in each cylinder. A turbo/supercharged engine produces more power overall than the same engine without the charging.

The typical boost provided by either a turbocharger or a supercharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50-percent more air into the engine. Therefore, you would expect to get 50-percent more power. It's not perfectly efficient, though, so you might get a 30-percent to 40-percent improvement instead.

The key difference between a turbocharger and a supercharger is its power supply. Something has to supply the power to run the air compressor. In a supercharger, there is a belt that connects directly to the engine. It gets its power the same way that the water pump or alternator does. A turbocharger, on the other hand, gets its power from the exhaust stream. The exhaust runs through a turbine, which in turn spins the compressor
There are tradeoffs in both systems. In theory, a turbocharger is more efficient because it is using the "wasted" energy in the exhaust stream for its power source. On the other hand, a turbocharger causes some amount of back pressure in the exhaust system and tends to provide less boost until the engine is running at higher RPMs. Superchargers are easier to install but tend to be more expensive.hope this helps,if you guys are wondering y i am posting on this forum. i just like the car and its new thanks. and yes i drive a hyundai 2003 tib
:D

do a twin turbo system and put one by the front wheels and the other by the back wheels ;)

If you used a small turbo/intercooler, and got rid of the precats, while moving the battery to the rear of the car you would be pretty close to 50/50.

Big Turbo, Big Sub box, problem solved.

well I've got the sub box

big turbo, big sub box

same acceleration ;)

nice copy/paste from howstuffworks.com

If you really want to keep 50/50 the only easy way I can see to to do it is to put the battery in the trunk somewhere.

That should equal it out nicely.

Personally, I don't think it is that big of a deal.

-Mr. Wigggles

nice copy/paste from howstuffworks.com

lol

Originally posted by Zio
nice copy/paste from howstuffworks.com I was just trying too help YOUR members with the info that they ask about . that has been up for like two years on how stuff works.com and yes i was wating for sombody too say somthing like that. OHH NO IM BUSTED:eek:

Does anybody knows if Mazda has a turbo version on the works?

Lots of rumors but i hear no.

Anyone notice that all literature usually states near 50/50 distribution?

Because it is 53/47 I believe not 50/50.

Originally posted by Wing
Because it is 53/47 I believe not 50/50.

...it's not quite that bad... that's actually the 350Z's factory balance.

Originally posted by Pulsr
if i decide to turbo my car will i throw off the 50/50 weight ratio?
You throw 50/50 off by sitting in your car...

Originally posted by Vette Dude

You throw 50/50 off by sitting in your car...

LOL, just slide the seat all the way back and use some long platform shoes.

You should not worry about your weight distribution right now. You should have quite a while to "decide" if you would like to turbocharge your car. I don't see a turbo kit happening in the near future. Even then there are only a handful of companies that you should even consider buying a turbo kit from for your 8.

Originally posted by j_dogg13b
You should have quite a while to "decide" if you would like to turbocharge your car. I don't see a turbo kit happening in the near future.

...one wouldn't need to wait if they decided to build one themselves (and can be done with better results than a kit...but usually isn't cheaper).

mazda version not yet just rumors
but trust in japan made one

Aqui lo tenemos, HKS se mueve y me sorprende.

HKS turbo progect is not e secret.

y cant put the photo!!!

wat i have to do?

LO TENGO

...........now reply.

woooh thats mad

Originally posted by m0j0
woooh thats mad

what's mad?? that article shows absolutely nothing... the exhaust is the generic aftermarket unit that we see in all the mags (is there any amount of differenciation, other than that weird pre-muffler 3rd tip on the blitz??), a low rez pic of an under the hood shot (showing only a generic yellow foam "cai") with nothing that seems like a turbo, no tubing/ducting/anything, and especially no power claims in the text.

HKS is good
but I dont see a turbo either

Blow it up its there.Even at posted size i can make out some of it unless they put a horseshoe shape in the intake.

i think i see it too, dont know wat u guys are smoking get some glasses

Originally posted by mental pimp
i think i see it too, dont know wat u guys are smoking get some glasses

Hey Pimp, please circle it on the image...please for all of us. And BTW, we're smoking what you recomended...BS.

Is it just me or do you guys see a turbo?

WTH

is it turbo or not?

According to the RX-8 supplement (in Road and Track I believe) HKS was working on a turbo.

However, I don't see one here. The easy way to tell is if anyone could translate the Japanese for us.

I think HKS will come out with a turbo like they said they were, but this just looks like an intake to me, but it is very hard to tell anything.

-Mr. Wigggles

since ive never seen this, im guessing its the top of the turbo

no i want those coil overs

Originally posted by mental pimp
since ive never seen this, im guessing its the top of the turbo

You said it yourself...now you see it?! :p

Originally posted by RX8-TX


You said it yourself...now you see it?! :p

And I didn't even have to lift my finger.

BTW, I guess that's only an aftermarket air-intake [period]

maby im rong
maby is induccion kit
maby

it doesnt look like it, wat are u gonna do? hit me :p

I've heard on some RX-8 advertisements that it will be 50/50 no matter if you have passengers or not

Originally posted by mental pimp
it doesnt look like it, wat are u gonna do? hit me :p

Only if you put your NOSE in front of my fist and lean forward.

HAHAHAHAHAHHAHAA you guys made my laugh my ass off for about 2 mins straight. the tard that posted the HKS turbo thread - nice one :) I saw this article in option mag and it doesnt say turbo, maybe in spanish turbo means throttle body? MUIAHAHHA

jua jua jua............
veri fani
ME PARTO eres un cachondo.
i postet to fast thats the reson.

Originally posted by Efini 8
HAHAHAHAHAHHAHAA you guys made my laugh my ass off for about 2 mins straight. the tard that posted the HKS turbo thread - nice one :) I saw this article in option mag and it doesnt say turbo, maybe in spanish turbo means throttle body? MUIAHAHHA

eres un come mierda, retrasado mental es tu mama

que te acuestes

efini
I laughed after reading your post
good one

Just a suction kit. HKS says they have no plan as of yet to make a turbo kit.

This is from the head Salesman and one of the mechs I know.

Who says 6psi wont kick you in the pants? Look at the compression ratio for the renesis rotors. They only need 6 psi to safely take you to another level in the 8..

spectators/speculators...

thank you jt
good to see you back on the site

Yeah thanks man..

I was in Cali for Sevenstock, so I didnt have too much time to stop by, but im back hehe

Maybe the ad said "Tornado" Air filter so he thought turbo?? lol

I agree. Props for the maginfication. I remeber reading that same pargraph out of the leaflet at the dealership about HKS, and the turbo kit. I also remeber reading something about a supercharger. HKS-USA reps are saying that they either don't know or nothing is planed. We'll see what will come to pass.

Check your PMs, SSR Enginering.:)

If you owned an rx7 then you know who pettit racing is. If you're new to the rotary club......Pettit racing is one of the best rx7 performance shops in the country. The're notoriously expensive, but everyone would agree that if they had the money, the'd take their car to pettit. Anyways, my friend was down there this weekend, and told them that I sold my FD for an rx8, and that if they had anything in the works I would be interested in being a guinnea pig. Their reply was that the're working on a supercharger, and to check back in a month. I'll head over there this week to confirm, and to get any details I can. Just thought y'all would like to know.

thats interesting......i hadnt thought of s/c the 8 though......but its somthing to think about
now boost on the other hand ;-)

keep up posted!!


andrew

I'm very curious. Personal experience would say to use a ProCharger. They make THE BEST superchargers I've ever used. Everything is self contained, cheap and easy to install. Installation will be different since this will be a custom application. Still I've had no problems with ProCharger ever. I'd love to see this under the hood. There's plenty of room for plumbing and mounting. I bet it looks very trick when it's complete.

I am going to but an RX-8 in about 6 months and I want to buy a turbo kit. I don't know much about them for a rotary engine so any advice would be great.

Thanks

my source in Mazdaspeed whom used to work for Garrett (manufacturer of turbochargers) as a head engineer... says the RENESIS can take only minimal boost pressures - 5-6 psi. Most likely the turbo kits will be developed for race purposes, custom purposes, and/or testing/prototyping.

I figured the engine might hae trouble with the turbos but thanks.

really just a matter of time
there is about 4 companies working on turbos now and more is to be released soon

I own a rx8 and i want to put a turbo but dont now anything about them for the rotary motors nor do i know where to find them can any one help me? also do you of any good sites besides www.acostamotorsports.com for parts(performance)?

Originally posted by MRMYKEEVIL
I own a rx8 and i want to put a turbo but dont now anything about them for the rotary motors nor do i know where to find them can any one help me? also do you of any good sites besides www.acostamotorsports.com for parts(performance)?

The RX-8 is too new for the aftermarket to release any type of Turbo kit for it (unless you want to go custom). Besides that, I suggest you read some more about Turbochargers, and the RX-8's engine in general so you know what you will be doing to your car. The motor on your car was not meant to be turbocharged with its high compression, and with its new design its taking the aftermarket alittle longer to come up with something. Lastly, the search button is your friend :) , use it to find more information on what you want to know.

yea trust have one allready dont they?
a td06 i think, td06's are pretty good turbos very quick spooling, id like to see the dyno numbers once they are released


andrew

We are working on a turbo kit and it will be done within the next week or so ;)

greddy already has a kit out in japan already...mazda r&d will be releasing the supercharger kit by early next year or so...

Can u confirm supercharger??If so info please.

www.corksport.com

Saw nothing about FI with the 8.

mental pimp i dont see anything about a supercharger on that site. Can you specify?

no FI info
but some cool parts

mental you liar J/k

Originally posted by Crashunit
The motor on your car was not meant to be turbocharged with its high compression...

That's completely untrue....